The present invention relates to an apparatus and method for treating gases. More particularly, the present invention relates to an apparatus and method for desulphurizing natural gas where the process is capable of running relatively continuously, safely and economically, with low maintenance required.
Gases, particularly natural gas, often contain unwanted sulphuric gaseous compounds, such as H.sub.2 S. It is desirable to remove these sulphuric gases before substantial transmission of the natural gas has taken place, because the sulphuric gases are highly corrosive or react to form corrosive substances, such as sulfuric acid. Further, the smell of many of the sulphuric gases is unpleasant, and can be a health hazard to those exposed to it. On the other hand, while it is desired to remove sulphuric gases from natural gas, the relatively small amount of sulphuric gases found by percentage in natural gas requires that the extraction be economical.
A method of desulphurizing natural gas known in the art involves treating the natural gas chemically with ferric oxide, Fe.sub.2 O.sub.3, otherwise known as red iron oxide. The ferric oxide is reacted with the sulphuric gaseous compound in a manner which removes the sulphur from the gas and changes the Fe.sub.2 O.sub.3 to ferrous oxide, Fe.sub.3 O.sub.4, otherwise known as black iron oxide.
This black iron oxide, Fe.sub.3 O.sub.4, must be changed back to red iron oxide, Fe.sub.2 O.sub.3, so that the process may continue. It is at this point that methods used in the prior art have encountered difficulty.
One of the aspects of making the desulphurization process economical is the minimizing of the labor required to run and maintain the process. Also, since most natural gas wells flow relatively steady, it is desired to obtain a process which runs relatively constantly, so that the well does not have to be shut in while the process is being repaired or maintained. In the prior art, red iron oxide has been used in the desulphurization process by contacting wood shavings treated in a red iron oxide solution. The wood shavings are mixed in the solution, allowed to dry and then inserted into the process for purposes of reacting with the sulfurous compounds. However, after going through the process, the treated wood chips must be replaced or retreated, to turn the black iron oxide back to red iron oxide. Normally the black iron oxide in the wood chips is changed back to red iron oxide by removing the chips from the process and spreading them on the ground for a length of time sufficient to allow them to "rust" back to red iron oxide. This operation is labor intensive, because the chips must be removed and spread on the ground, and is also costly in terms of lost production because the well must be shut in.
Another method used in the prior art for desulphurizing natural gas involves the use of arsenic in the process. However, this process cannot be kept as a completely closed system, so that arsenic ponds must be maintained around the well sites. These ponds pose significant health hazards.
The present invention overcomes these inadequacies in the prior art by providing a desulphurization apparatus and method which runs relatively continuously, safely, economically and with low maintenance.
Therefore, it is an object of the present invention to provide a desulphurization apparatus and method for natural gas which runs relatively continuously, safely, economically and with low maintenance.
It is a further object of the present invention that the apparatus and method effectively remove sulphuric gases from natural gas.
Other objects of the present invention, although not mentioned above, will become obvious during the following description of the preferred embodiment, and they are intended to fall within the objects of the present invention.